Cyanomethylation of Substituted Fluorenes and Oxindoles with Alkyl Nitriles
作者:Gang Hong、Pradip D. Nahide、Marisa C. Kozlowski
DOI:10.1021/acs.orglett.0c00160
日期:2020.2.21
cyanomethylenation from alkyl nitriles of sp3 C–H bonds to afford quaternary carbon centers is described. This oxidative protocol is operationally simple and features good functional group compatibility. This method provides a novel approach to highly functionalized fluorene and oxindole derivatives, which are commonly used in material and pharmaceutical areas. Control experiments provide evidence of a radical
Palladium-catalysed direct cross-coupling of secondary alkyllithium reagents
作者:Carlos Vila、Massimo Giannerini、Valentín Hornillos、Martín Fañanás-Mastral、Ben L. Feringa
DOI:10.1039/c3sc53047g
日期:——
Palladium-catalysed cross-coupling of secondary C(sp3) organometallic reagents has been a long-standing challenge in organic synthesis, due to the problems associated with undesired isomerisation or the formation of reduction products. Based on our recently developed catalytic C–C bond formation with organolithium reagents, herein we present a Pd-catalysed cross-coupling of secondary alkyllithium reagents with aryl and alkenyl bromides. The reaction proceeds at room temperature and on short timescales with high selectivity and yields. This methodology is also applicable to hindered aryl bromides, which are a major challenge in the field of metal catalysed cross-coupling reactions.
Au-Catalyzed Biaryl Coupling To Generate 5- to 9-Membered Rings: Turnover-Limiting Reductive Elimination versus π-Complexation
作者:Tom J. A. Corrie、Liam T. Ball、Christopher A. Russell、Guy C. Lloyd-Jones
DOI:10.1021/jacs.6b10018
日期:2017.1.11
The intramolecular gold-catalyzed arylation of arenes by aryl-trimethylsilanes has been investigated from both mechanistic and preparative aspects. The reaction generates 5- to 9-membered rings, and of the 44 examples studied, 10 include a heteroatom (N, O). Tethering of the arene to the arylsilane provides not only a tool to probe the impact of the conformational flexibility of Ar-Au-Ar intermediates
A general and efficient synthesis of substituted fluorenes and heterocycle-fused indenes containing thiophene or indole rings utilizing a Suzuki–Miyaura coupling and acid-catalyzed Friedel–Crafts reactions as key steps
作者:Guijie Li、Erjuan Wang、Haoyi Chen、Hongfeng Li、Yuanhong Liu、Peng George Wang
DOI:10.1016/j.tet.2008.07.021
日期:2008.9
A general and efficient synthesis of fluorenes or heterocycle-fused indenes including 3-thia-cyclopenta[a]indenes, 9-thia-indeno[1,2-a]indenes, 5,6-dihydroindeno[2,1-b]indoles has been developed. This methodology is realized by a multistep protocol involving first preparation of ortho-formylbiaryls through Suzuki–Miyaura coupling of o-bromobenzaldehydes with arylboronic acids or the coupling of aryl
芴或杂环稠合的茚基的一般有效合成方法,包括3-噻吩环戊[ a ]茚,9-噻吩[1,2- a ]茚,5,6-二氢茚并[ 2,1- b ]吲哚已经被开发出来。这种方法是由涉及的第一制备多步协议实现邻-formylbiaryls通过铃木-宫浦耦合的ø-溴苯甲醛与芳基硼酸的结合或芳基卤化物与2-甲酰基苯硼酸的偶联,然后进行Brignard加成反应或Lewis酸催化的Friedel-Crafts环化反应,形成所需的芴或茚环。该方法具有许多优点,例如产率高,选择性高,反应条件温和,起始原料容易获得等。
Acidity of hydrocarbons. Ionisation constants for some substituted 9-phenylfluorenes
作者:Anthony F. Cockerill、John E. Lamper
DOI:10.1039/j29710000503
日期:——
The pKa values of a series of substituted9-phenylfluorenes have been measured. In conjunction with earlier studies, the results enable the establishment of an H– acidity function for 25–97% aqueous dimethyl sulphoxide containing tetramethylammonium hydroxide. It is indicated that this scale does not parallel the acidity function based on the ionisation of aniline indicators in the more aqueous solutions
已经测量了一系列取代的9-苯基芴的p K a值。在与以前的研究相结合,结果使建立的ħ -为25-97%的含水二甲亚砜含有氢氧化四甲铵酸度函数。结果表明,在更多水溶液中,基于苯胺指示剂的电离,该比例与酸度功能不平行。芴环中的取代基对烃酸度的影响大于9-苯基核中的取代基。通过使用改良的Hammett方程,取代基与烃酸度的影响相关,表明9-苯环与芴核的平面度之间的距离约为。 39°,接近分子轨道计算先前预测的值。